LED lighting apparatus

ABSTRACT

An LED lighting apparatus includes an LED substrate, a LED chip, a sealing resin member, and a reflecting face. The LED substrate has a main surface. The LED chip is mounted on the main surface of the LED substrate. The sealing resin member is made of a material that transmits light from the LED chip. The sealing resin member covers the LED chip. The sealing resin member has a shape bulging in the direction in which the main surface faces. The reflecting face surrounds the sealing resin member.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a lighting apparatus using a lightemitting diode (LED).

2. Description of Related Art

Various types of LED lighting devices have been conventionally proposed.For example, JP-A-2003-329978 discloses an LED lighting device providedwith a plurality of LED chips and a reflector placed behind the LEDchips. In this lighting device, the reflector has a plurality ofreflecting faces formed to correspond to the plurality of LED chips.

In the above lighting device, one corresponding LED chip is placed infront of each reflecting face. For this reason, part of light reflectedfrom the reflecting face is blocked by the LED chip, preventingimprovement in the brightness of the lighting device.

JP-A-2013-55172 discloses an LED lighting device provided with aplurality of LED chips and a plurality of resin covers each covering theLED chips. The resin covers are formed by dropping a liquid resinmaterial and hardening the material. This technique however causesvariations in the shape, height, etc. of the resin covers, preventingimprovement in the brightness of the lighting device.

SUMMARY OF THE INVENTION

The present invention has been proposed under the circumstancesdescribed above. It is therefore an objective of the invention toprovide an LED lighting apparatus suitable for brightness improvement.

An LED lighting apparatus presented according to the first aspect of theinvention includes: an LED substrate having a main surface; an LED chipmounted on the main surface of the LED substrate; a sealing resin membermade of a material that transmits light from the LED chip, the membercovering the LED chip and having a shape of bulging in a direction inwhich the main surface faces; and a reflecting face surrounding thesealing rein member.

An LED lighting apparatus presented according to the second aspect ofthe invention includes: an LED substrate having a main surface and areverse surface; a plurality of LED chips mounted on the main surface ofthe LED substrate; a plurality of sealing resin members covering theplurality of LED chips, each being made of a light-transmissive materialand having a shape of bulging in a direction in which the main surfacefaces; and a plurality of cases supported by the LED substrate. Each ofthe plurality of cases includes two reflecting faces adjacent as viewedin the thickness direction of the LED substrate, and each of thereflecting faces surrounds one of the plurality of LED chips.

Other features and advantages of the invention will become more apparentfrom the following detailed description taken with reference to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view showing an LED lighting apparatus according to thefirst embodiment of the invention.

FIG. 2 is a front view showing the lighting apparatus of FIG. 1.

FIG. 3 is a side view showing the lighting apparatus of FIG. 1.

FIG. 4 is a perspective view showing part of the lighting apparatus ofFIG. 1.

FIG. 5 is a plan view of the part shown in FIG. 4.

FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 5.

FIG. 7 is a cross-sectional view showing part of the lighting apparatusof FIG. 1.

FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 5.

FIG. 9 is a plan view showing an auxiliary substrate of the lightingapparatus of FIG. 1.

FIG. 10 is a bottom view of the auxiliary substrate shown in FIG. 9.

FIG. 11 is a cross-sectional view showing part of an LED lightingapparatus according to the second embodiment of the invention.

FIG. 12 is a cross-sectional view showing a process step of a productionmethod for the lighting apparatus of FIG. 11.

FIG. 13 is a cross-sectional view showing another process step of theproduction method.

FIG. 14 is a cross-sectional view showing yet another process step ofthe production method.

FIG. 15 is a cross-sectional view showing yet another process step ofthe production method.

FIG. 16 is a cross-sectional view showing part of an LED lightingapparatus according to the third embodiment of the invention.

FIG. 17 is a perspective view showing an LED lighting apparatusaccording to the fourth embodiment of the invention.

FIG. 18 is a cross-sectional view taken along line XVIII-XVIII in FIG.17.

FIG. 19 is a cross-sectional view showing a process step of a productionmethod for the LED lighting apparatus of FIG. 17.

FIG. 20 is a cross-sectional view showing another process step of theproduction method for the LED lighting apparatus of FIG. 17.

FIG. 21 is a cross-sectional view showing yet another process step ofthe production method for the LED lighting apparatus of FIG. 17.

FIG. 22 is a cross-sectional view showing yet another process step ofthe production method for the LED lighting apparatus of FIG. 17.

FIG. 23 is a cross-sectional view showing an alteration of the LEDlighting apparatus of FIG. 17.

FIG. 24 is a cross-sectional view showing another alteration of the LEDlighting apparatus of FIG. 17.

FIG. 25 is a cross-sectional view showing an LED lighting apparatusaccording to the fifth embodiment of the invention.

FIG. 26 is a cross-sectional view showing an LED lighting apparatusaccording to the sixth embodiment of the invention.

FIG. 27 is a cross-sectional view showing an LED lighting apparatusaccording to the seventh embodiment of the invention.

FIG. 28 is a plan view showing an LED lighting apparatus according tothe eighth embodiment of the invention.

FIG. 29 is a front view showing the LED lighting apparatus of FIG. 28.

FIG. 30 is a side view showing the LED lighting apparatus of FIG. 28.

FIG. 31 is a perspective view showing part of the LED lighting apparatusof FIG. 28.

FIG. 32 is a plan view showing part of the LED lighting apparatus ofFIG. 28.

FIG. 33 is a cross-sectional view taken along line XXXIII-XXXIII in FIG.32.

FIG. 34 is a cross-sectional view taken along line XXXIV-XXXIV in FIG.32.

FIG. 35 is a plan view showing an auxiliary substrate of the LEDlighting apparatus of FIG. 28.

FIG. 36 is a bottom view showing the auxiliary substrate.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will be specificallydescribed hereinafter with reference to the accompanying drawings.

FIGS. 1 to 10 show an LED lighting apparatus according to the firstembodiment of the invention. The lighting apparatus A1 shown includes asubstrate (LED substrate) 1, a plurality of LED chips 2, a plurality ofsealing resin members 3, a plurality of cases 4, an auxiliary substrate5, and a cover 7.

Lighting apparatuses according to the invention, including the lightingapparatus A1 of the first embodiment, can be used for various purposesas light sources. For example, the lighting apparatus A1 can be used asa lighting means for a road traffic information system.

The substrate 1 supports a plurality of LED chips 2. Power supply pathsare formed in the substrate 1 for allowing the plurality of LED chips 2to emit light. The substrate 1 has a main surface 1 a and a reversesurface 1 b facing opposite to each other. In FIG. 2, the main surface 1a faces upward in the z direction, and the reverse surface 1 b facesdownward in the z direction. The plurality of LED chips 2 are mounted onthe main surface 1 a. The size of the substrate 1 is about 116 mm in thex direction and about 55 mm in the y direction, for example. The size ofthe substrate 1 in the z direction (thickness) is in the range of 0.5 mmto 1.5 mm, and it may be about 1.0 mm, for example.

As shown in FIG. 6, the substrate 1 includes an insulating base 11 and awiring pattern 12. The insulating material constituting the base 11 isnot specifically limited. In this embodiment, the base 11 is formed of aplurality of layers made of a glass epoxy resin placed on top of oneanother. The main surface 1 a of the substrate 1 described above isvirtually constituted by the main surface (top surface in FIG. 7) of thebase 11, and the reverse surface 1 b of the substrate 1 corresponds tothe reverse surface of the base 11. As used herein, therefore, the mainsurface of the base 11 is denoted by 1 a, and the reverse surface of thebase 11 by 1 b.

The wiring pattern 12 includes portions formed on the main surface 1 aof the base 11, portions formed on the reverse surface 1 b thereof, andportions formed inside the base 11. The wiring pattern 12 is made of ametal such as Cu, Pd, Ni, and Au. The wiring pattern 12 may beconstituted by a single layer, or of a plurality of layers placed on topof one another. For the wiring pattern 12 constituted by a plurality oflayers, the layers may be formed of the same metal or different metals(it is preferable that at least the outermost layer be formed of Au). Asshown in FIGS. 5 to 7, the wiring pattern 12 includes a plurality of diebonding pads 12 a, a plurality of wire bonding pads 12 b, a plurality ofintermediate layers 12 d and 12 e, and a plurality of through holeportions 12 f.

Each die bonding pad 12 a is a portion to which its corresponding LEDchip 2 is die-bonded, and is formed on the main surface 1 a of the base11. In this embodiment, the die bonding pad 12 a is in a shape of asquare having a length of one side of about 1.4 mm. As shown in FIG. 5,each wire bonding pad 12 b is formed to be apart outwardly from itscorresponding die bonding pad 12 a and surround the die bonding pad 12a. The inner rim of the wire bonding pad 12 b is similar in shape to thedie bonding pad 12 a: it is in a shape of a square having a length ofone side of about 1.7 mm, for example. An outer rim 12 c of the wirebonding pad 12 b (see FIG. 7) is in a shape of a circle having adiameter of about 2.6 mm, for example. As will be described later, theplurality of die bonding pads 12 a are arranged such that each diebonding pad is located at an apex of a triangle. The wiring pattern 12does not include any portion connected to the die bonding pads 12 a orthe wire bonding pads 12 b on the main surface 1 a.

A resist layer 13 is formed on the main surface 1 a. The resist layer13, made of an insulating resin, has a plurality of circular openingsfor exposing the die bonding pads 12 a and the wire bonding pads 12 b.The diameter of the openings is about 2.9 mm, for example.

As shown in FIG. 7, the through hole portions 12 f are connected to thedie bonding pads 12 a and the wire bonding pads 12 b. Each through holeportion 12 f forms a conducting path extending in the direction of thethickness of the base 11 (z direction). The die bonding pads 12 a are inconduction with the intermediate layer 12 e via the through holeportions 12 f. The wire bonding pads 12 b are in conduction with theintermediate layer 12 d via their through hole portions 12 f. Theintermediate layers 12 d and 12 f are formed into predetermined shapesinside the base 11, forming conducting paths spreading in the xy plane.

The plurality of LED chips 2 are die-bonded to the plurality of diebonding pads 12 a on the main surface 1 a of the substrate 1. In thisembodiment, as will be understood from FIGS. 1 and 5, the LED chips 2are arranged such that each LED chip is located at an apex of atriangle. The length of one side of the triangle is about 8.0 mm, forexample.

As shown in FIG. 7, each LED chip 2 has a semiconductor layer 20, anupper electrode 21, and a lower electrode 22. The semiconductor layer 20has a structure of an n-type semiconductor layer, an active layer, and ap-type semiconductor layer placed on top of one another. In thisembodiment, the semiconductor layer 20 is made of an AlInGaNpsemiconductor and a GaAs semiconductor, for example, and the LED chip 2emits infrared light.

The upper electrode 21 is formed on the top surface of the semiconductorlayer 20. Ends of two wires 25 are bonded to the upper electrode 21. Theother ends of the two wires 25 are bonded to the common wire bonding pad12 b. These wires 25 extend in the opposite directions from the LED chip2 as viewed from top. The lower electrode 22 is formed on the bottomsurface of the semiconductor layer 20 and joined to the die bonding pad12 a with a conductive joining material 26.

The plurality of sealing resin members 3, each covering onecorresponding LED chip 2, are made of a material that transmits lightfrom the LED chips 2. As the material of the sealing resin members 3, atransparent epoxy resin or silicone resin may be used. Each sealingresin member 3 also covers the two wires 25. The sealing resin member 3has a shape of bulging in the direction in which the main surface 1 afaces, i.e., upward in the z direction.

The sealing resin member 3 has an outer rim 3 a. In this embodiment, theouter rim 3 a coincides with the outer rim 12 c of the wire bonding pad12 b. Such a sealing resin member 3 is formed, for example, by droppinga liquid epoxy resin or silicone resin material onto the LED chip 2 viaa nozzle, etc. after completion of the die-bonding of the LED chip 2 tothe die bonding pad 12 a and the bonding of the two wires 25. Thedropped liquid resin material covers the LED chip 2 and the two wires 25and also spreads over the main surface 1 a. By setting the drop amount,etc. properly, the spread of the resin material can be stopped at theouter rim 12 c of the wire bonding pad 12 b by the action of surfacetension. The resin material is then UV-cured or thermally cured, toobtain the sealing resin member 3 bulging upward in the z direction.

The plurality of cases 4 are provided for reflecting part of lightemitted from the LED chips 2 upward in the z direction. In thisembodiment, each case 4 is formed of a member made of a whitepolycarbonate resin with A1 evaporation coating applied thereto. Theinvention is however not limited to this. For example, if a sufficientlyhigh reflectivity is secured, the case may be formed of only a whiteresin with no coating applied. Alternatively, the case 4 may be formedof a metal instead of a resin.

As shown in FIGS. 4 to 6, each case 4 in this embodiment has tworeflecting faces 4 a adjacent to each other. Each reflecting face 4 ahas a ring shape surrounding the corresponding sealing resin member 3.The reflecting face 4 a is a concave curved surface, and, in thisembodiment, an aspheric surface. The height of the reflecting face 4 a(size in the z direction) is larger than that of the sealing resinmember 3. As is evident from FIG. 6, an inner rim 4 b of the reflectingface 4 a is located outside the outer rim 3 a of the sealing resinmember 3 and apart from the outer rim 3 a.

As shown in FIG. 1, the plurality of cases 4 each having two reflectingfaces 4 a are arranged in correspondence with the plurality of LED chips2 and the plurality of sealing resin members 3. As shown in FIGS. 5 and8, two protrusions 41 are formed on each case 4. The two protrusions 41are placed between the two reflecting faces 4 a at positions apart fromeach other in the direction perpendicular to the direction in which thetwo reflecting faces 4 a are apart. The two protrusions 41 do notoverlap either of the two reflecting faces 4 a as viewed in the zdirection.

Each protrusion 41 engages with a fixing hole 11 a formed through thesubstrate 1, thereby securing the case 4 with respect to the substrate1. In this embodiment, the protrusion 41 has a fixed-diameter portion 41a and a large-diameter portion 41 b larger in diameter than thefixed-diameter portion 41 a. The fixed-diameter portion 41 a,constituting a root portion of the protrusion 41, fits in through thefixing hole 11 a of the substrate 1. The large-diameter portion 41 b,constituting a tip portion of the protrusion 41, expands from thereverse surface 1 b of the substrate 1. The large-diameter portion 41 bis larger in diameter than the diameter of the fixing hole 11 a. Withthe large-diameter portion 41 b engaging with the reverse surface 1 b,the protrusion 41 is prevented from coming out of the fixing hole 11 a.Such a large-diameter portion 41 b can be formed, for example, byforming a rod-shaped portion having a fixed diameter on the case 4,inserting the rod-shaped portion through the fixing hole 11 a of thesubstrate 1, and then deforming the tip of the rod-shaped portion byheating (heat caulking). In this embodiment, the case 4 is secured tothe substrate 1 with only the two protrusions 41, with no adhesive used.

The auxiliary substrate 5 includes a base made of a glass epoxy resin,for example, and a wiring pattern formed on this base, and a pluralityof electronic components 51 and two connectors 52 are mounted on theauxiliary substrate 5. FIG. 9 is a plan view of the auxiliary substrate5, and FIG. 10 is a bottom view thereof. The auxiliary substrate 5 isplaced facing the reverse surface 1 b of the LED substrate 1 in thisembodiment (see FIG. 2), and is in parallel with the LED substrate 1 inthis embodiment. The auxiliary substrate 5 and the LED substrate 1 arecoupled to each other with four coupling rods 53. Also, a plurality ofconductive rods 54 are attached to the auxiliary substrate 5 and the LEDsubstrate 1. Each conductive rod 54 includes a conductive member made ofa metal, and the conductive member may be covered with an insulatingcoating. The conductive rod 54 connects an appropriate position of thewiring pattern 12 formed on the reverse surface 1 b of the LED substrate1 and an appropriate position of the wiring pattern of the auxiliarysubstrate 5.

The plurality of electronic components 51 are for activating or lightingup the plurality of LED chips 2, and include ICs for drive control, chipresistors, and diodes, for example. In this embodiment, the plurality ofelectronic components 51 also include a plurality of capacitors 51 a.These capacitors 51 a have a function of storing electric power forallowing the plurality of LED chips 2 to emit light with high brightnesssimultaneously. As shown in FIGS. 2, 3, 9, and 10, part of the pluralityof capacitors 51 a are mounted on the top surface (surface facing theLED substrate 1) of the auxiliary substrate 5 while the remainder on thebottom surface thereof.

The two connectors 52 are used when the lighting apparatus A1 isincorporated in a main system (e.g., a traffic information system), andmounted on the bottom surface of the auxiliary substrate 5.

The cover 7 is provided to cover the plurality of sealing resin members3 and the plurality of cases 4, and made of a transparent resin, forexample. In FIG. 1, the cover 7 is represented by the two-dot chainline. The cover 7 has a function of protecting the plurality of sealingresin members 3 and the plurality of cases 4. Fine prisms may be formedon the surface of the cover 7 to refract light output from the pluralityof LED chips 2 in a specific direction.

Next, the workings of the lighting apparatus A1 will be described.

In the lighting apparatus A1, as shown in FIG. 6, light rays, out of thelight emitted from each LED chip 2, travelling upward in the z direction(the direction in which the main surface 1 a faces) are output upwardfrom the sealing resin member 3. At this time, with the sealing resinmember 3 having a shape of bulging upward in the z direction, the lightrays travel in parallel (or roughly in parallel) in the z direction(i.e., the directionality of light is enhanced). As for light raystravelling sideways or obliquely upward from the LED chip 2, they arereflected by the reflecting face 4 a after having been output from thesealing resin member 3. Such light rays therefore travel upward in the zdirection. In this way, much of the light emitted from the LED chip 2can be output in a predetermined direction, and thus improvement in thebrightness of the lighting apparatus A1 can be achieved.

According to this embodiment, the outer rim 3 a of the sealing resinmember 3 coincides with the outer rim 12 c of the wire bonding pad 12 b.This is because the above-described resin material dropped onto the mainsurface 1 a for formation of the sealing resin member 3 is dammed up atthe outer rim 12 c of the wire bonding pad 12 b. That is, according tothis embodiment, the liquid resin material is prevented from spreadingover the main surface 1 a, and thus the sealing resin member 3 can beavoided from taking an inappropriate shape such as a flat shape. Thewire bonding pad 12 b is shaped to completely surround the die bondingpad 12 a, and the outer rim 12 c thereof is continuous over the entireperiphery of the die bonding pad 12 a. This is suitable for finishing ofthe sealing resin member 3 into a desired shape (e.g., a shape having asmooth curved surface).

In this embodiment, since the upper electrode 21 and the wire bondingpad 12 b are connected with the two wires 25, a large current can besupplied to the LED chip 2. This is advantageous for increase in theoutput of the LED chip 2, i.e., improvement in the brightness of thelighting apparatus A1. Also, with the two wires 25 extending in theopposite directions from the LED chip 2, the sealing resin member 3having good shape balance can be formed.

In this embodiment, the reflecting face 4 a is constituted by the case 4supported by the substrate 1. Therefore, by simply securing the case 4to the substrate 1, the reflecting face 4 a can be placed at a desiredposition with respect to the LED chip 2 and the sealing resin member 3.Moreover, having a ring shape as viewed in the z direction and alsohaving an aspheric shape, the reflecting face 4 a can reflect light fromthe LED chip 2 efficiently in the z direction.

In this embodiment, the case 4 is made of a resin member subjected tometal coating. Thus, the case 4 can be easily formed into a desiredshape and size. Also, with the metal coating, the reflecting face 4 ahaving a desired reflectivity can be easily formed.

In this embodiment, a plurality of LED chips are mounted on one face ofthe substrate 1. Thus, the lighting apparatus A1 can be provided as ahigh-brightness light-source device that emits planar light.

In this embodiment, a plurality of cases 4 that are not coupled mutuallyare used. Therefore, even if an individual case 4 is thermally deformedat use, this will not cause undue deformation of the substrate 1. Also,each case 4 has two reflecting faces 4 a separately surrounding twoadjacent LED chips 2. Therefore, since the number of cases 4 can be ahalf of the total number of LED chips 2, the efficiency of theproduction process can be enhanced.

In this embodiment, the LED chips 2 are arranged such that each LED chipis located at an apex of a triangle. Thus, planar light with a uniformbrightness distribution can be output.

In this embodiment, the case 4 is secured to the substrate 1 by engagingthe protrusions 41 with the fixing holes 11 a of the substrate 1. Thisindicates that most of the bottom surface of the case 4 is in contactwith the substrate 1 but not secured thereto. Therefore, for example,even if one of the case 4 and the substrate 1 is thermally deformed, theother is prevented from being affected by this. Also, with theprotrusions 41 provided between the two reflecting faces 4 a adjacent toeach other as viewed in the z direction, the case 4 can be secured tothe substrate 1 in balance, and increase in the size of the case 4 canbe avoided. Moreover, the arrangement of the two protrusions in thedirection perpendicular to the direction in which the two adjacentreflecting faces 4 a are apart is suitable for securing the case 4 inbalance. Since the protrusions 41 do not overlap the reflecting faces 4a as viewed in the z direction, the reflecting faces 4 a can beprevented from undue deformation due to heat caulking by which the case4 is attached to the substrate 1.

In this embodiment, the plurality of LED chips 2 are provided on onesurface of the substrate 1, and the auxiliary substrate 5 is secured tothe opposite surface thereof. Therefore, light outgoing from the LEDchip 2 will not be blocked by the plurality of electronic components 51.Also, by placing the auxiliary substrate 5 with an appropriate spacingfrom the substrate 1, a desired number of electronic components can beplaced on both surfaces of the auxiliary substrate 5. In particular,since the capacitors 51 a are needed to allow the plurality of LED chips2 to emit light with high brightness simultaneously, provision of manycapacitors 51 a contributes to improvement in the brightness of thelighting apparatus A1. The placement in this embodiment, in which anumber of capacitors 51 a can be provided on both surfaces of theauxiliary substrate 5, is therefore advantageous in brightnessimprovement.

FIGS. 11 to 15 show an LED lighting apparatus according to the secondembodiment of the invention. In these drawings, the same or similarelements as or to those in the first embodiment described above aredenoted by the same reference characters.

As shown in FIG. 11, in the LED lighting apparatus A2 of the secondembodiment, the configuration of the sealing resin member 3 is differentfrom that in the above embodiment.

In the second embodiment, the sealing resin member 3 has a columnarportion 31 and a dome portion 32. The columnar portion 31 covers the LEDchip 2 and has an axial center extending in the z direction. Thetransverse cross section (perpendicular to the z direction) of thecolumnar portion 31 is circular, for example. The dome portion 32 isformed on the top surface of the columnar portion 31 and bulges upwardin the z direction.

The columnar portion 31 and the dome portion 32 may be formed of thesame material or different materials. Specifically, both the columnarportion 31 and the dome portion 32 may be formed of a transparent resin(e.g., an epoxy resin or a silicone resin). Alternatively, while thecolumnar portion 31 being formed of a transparent resin, the domeportion 32 may be formed of a material obtained by mixing a fluorescentmaterial into the transparent resin. The fluorescent material outputslight different in wavelength from the light emitted from the LED chip 2by being excited by the light from the LED chip 2. When the LED chip 2emits blue light, yellow light may be output from the fluorescentmaterial, for example. As a result, white light is finally output fromthe lighting apparatus A2.

FIGS. 12 to 15 show an example production method for the lightingapparatus A2.

First, a plurality of LED chips 2 are mounted on the substrate 1 (inFIG. 12, only one LED chip is shown). Two wires 25 are bonded to eachLED chip. A sheet S is stuck to the main surface 1 a of the substrate 1.The sheet S has a plurality of openings Sa. The openings Sa, formed tocorrespond to the plurality of LED chips 2, are each shaped and sized toaccommodate one LED chip 2. The thickness of the sheet S is larger thanthe height (size in the z direction) of the LED chip 2. The thickness ofthe sheet S is also made larger than the distance between the mainsurface 1 a and the highest position of the wires in the z direction.The sheet S is formed of a fluorocarbon resin, for example, but may beformed of a material other than this.

As shown in FIG. 13, each opening Sa in the sheet S is filled with aliquid resin material using a nozzle Nz, for example. The filling amountof the resin material in the opening Sa is an amount with which at leastthe LED chip 2 and the two wires 25 are completely covered with theresin material, and preferably an amount with which the surface of theresin material is flush with the top surface of the sheet S. The filledliquid resin material is exposed to heat or UV to harden the resinmaterial, thereby obtaining the columnar portion 31 (see FIG. 11).

As shown in FIG. 14, the sheet S is stripped off from the substrate 1.As shown in FIG. 15, a liquid resin material is dropped onto the topsurface of the columnar portion 31 using the nozzle Nz, for example. Thedrop amount of the resin material at this time is an amount with whichthe resin material at least covers the entire top surface of thecolumnar portion 31, and preferably an amount with which the resinmaterial takes a dome shape. The dropped liquid resin material isexposed to heat or UV to harden the resin material, thereby obtainingthe dome portion 32. Thereafter, the cases 4, the auxiliary substrate 5,etc. are attached to the LED substrate 1, to obtain the lightingapparatus A2.

Brightness improvement can be achieved also for the lighting apparatusA2. In particular, with the dome portion 32 provided on the columnarportion 31, the distance between the top surface of the sealing resinmember 3 and the LED chip 2 can be increased. For sealing resin members3 whose top surfaces are the same in shape, the directionality will bemore enhanced as the distance of the top surface from the LED chip 2 islonger.

FIG. 16 shows an LED lighting apparatus according to the thirdembodiment of the invention. The lighting apparatus A3 of thisembodiment has light guide members 6 in place of the cases 4 in thefirst and second embodiments described above. In this embodiment, thelight guide members 6 are prism lenses, but the invention is not limitedto this.

The prism lenses 6 are made of a transparent resin (e.g., acrylic),glass, or the like. Each of the prism lenses 6 has a recess portion 61,an outer side surface 62, and an outgoing surface 63.

The recess portion 61 opens downward and is closed upward (at the bottomof the recess portion). The prism lens 6 is joined to the substrate 1with an adhesive at the lower rim of the recess portion 61.

The recess portion 61 houses the sealing resin member 3 inside and has abottom surface 61 a and an inner side surface 61 b. The bottom surface61 a is located right above the sealing resin member 3 and is largerthan the sealing resin member 3 as viewed in the z direction. The bottomsurface 61 a is circular, for example, as viewed in the z direction, andhas a shape of bulging downward. With this shape, the bottom surface 61a functions as a convex lens.

The inner side surface 61 b, connecting the lower rim of the recessportion 61 and the bottom surface 61 a, is cylindrical in thisembodiment. The inner side surface 61 b is parallel to the z directionand located slightly outside the sealing resin member 3 as viewed in thez direction.

The outer side surface 62 is a surface extending from the lower end ofthe prism lens 6 to the upper end thereof. The outer side surface 62 isinclined so that the size of the cross section as viewed in the zdirection is larger as the position of the cross section is farther fromthe substrate 1 in the z direction. Also, the outer side surface 62 is acurved surface bulging obliquely downward, and is aspheric in thisembodiment. Light travelling laterally from the LED chip 2 passesthrough the sealing resin member 3 and enters the prism lens 6 at theinner side surface 61 b thereof. Thereafter, after being totallyreflected by the outer side surface 62, the light travels upward. Thatis, the outer side surface 62 in this embodiment functions as areflecting face 6 a.

The outgoing surface 63, connected to the upper end of the outer sidesurface 62, is a circular flat surface vertical to the z direction inthis embodiment. Light incident on the bottom surface 61 a of the recessportion 61 or light reflected by the reflecting face 6 a is output fromthe outgoing surface 63.

In the lighting apparatus A3, light travelling upward from the LED chip2 is enhanced in directionality by passing through the top surface ofthe sealing resin member 3 and the bottom surface 61 a of the prism lens6. Also, since the reflecting face 6 a totally reflects light, thebrightness will not be decreased.

FIGS. 17 and 18 show an LED lighting apparatus according to the fourthembodiment of the invention. The LED lighting apparatus A4 of thisembodiment includes a substrate (LED substrate) 1, a plurality of LEDchips 2, and a plurality of sealing resin members 3. The LED lightingapparatus A4 is used as a light source device for a dot matrixindicator, for example, but the invention is not limited to this.

The substrate 1 supports the plurality of LED chips 2 and alsoconstitutes power supply paths for allowing the LED chips 2 to emitlight. The substrate 1 has a main surface 1 a and a reverse surface 1 b,and includes a base 11 and a wiring pattern 12. The plurality of LEDchips 2 are mounted on the main surface 1 a.

The base 11 is made of an insulating material, which is, but notspecifically limited to, a glass epoxy resin, for example. In thisembodiment, the base 11 is formed of a plurality of layers each made ofa glass epoxy resin placed on top of one another.

In this embodiment, the wiring pattern 12 is formed on at least the mainsurface 1 a of the base 11, and made of a metal such as Cu, Pd, Ni, andAu. The wiring pattern 12 may be constituted by a single layer, or of aplurality of layers placed on top of one another. For the wiring pattern12 constituted by a plurality of layers, the layers may be formed of thesame metal or different metals (in this embodiment, at least theoutermost layer is formed of Au). The wiring pattern 12 includes diebonding pads 12 a and wire bonding pads 12 b.

The LED chips 2 are die-bonded to the die bonding pads 12 a, which areformed on the main surface 1 a. The wire bonding pads 12 b are formed onthe main surface 1 a and apart from the die bonding pads 12 a.

In this embodiment, a drive IC 17 and a connector 18 are provided on thesubstrate 1. The drive IC 17 performs control for allowing the pluralityof LED chips 2 to emit light. The connector 18 is used for attaching theLED lighting apparatus A4 to a main system, for example. The connector18 is in conduction with the wiring pattern 12.

The plurality of LED chips 2 are separately die-bonded to the pluralityof die bonding pads 12 a provided on the main surface 1 a of thesubstrate 1. In this embodiment, the plurality of LED chips 2 arearranged in a matrix.

As shown in FIG. 18, each of the LED chips 2 includes a semiconductorlayer 20, two upper electrodes 21, and a sub-mount substrate 24. Thesemiconductor layer 20 has a structure of an n-type semiconductor layer,an active layer, and a p-type semiconductor layer placed on top of oneanother. In this embodiment, the semiconductor layer 20 is formed of GaNsemiconductors, and the LED chip 2 emits blue light.

The two upper electrodes 21 are formed on the top surface of thesemiconductor layer 20. Ends of two wires 25 are bonded to the two upperelectrodes 21. The other ends of the wires 25 are bonded to the wirebonding pad 12 b. The two wires 25 extend in the opposite directionsfrom the LED chip 2. The sub-mount substrate 24, made of Si, forexample, supports the semiconductor layer 20. The sub-mount substrate 24is secured to the die bonding pad 12 a with a joining material 27.

Sealing resin members 3 each cover one corresponding LED chip 2, and aremade of a material that transmits light from the LED chip 2. As thematerial of the sealing resin members 3, a transparent resin (e.g., anepoxy resin or a silicone resin) is used, for example. Otherwise, amaterial obtained by mixing a fluorescent material into the transparentresin may be used. The fluorescent material emits yellow light by beingexcited by blue light from the LED chip 2. Having the aboveconfiguration, the LED lighting apparatus A4 finally emits white light.Alternatively, the fluorescent material may be one that emits red lightor green light by being excited by blue light.

In the LED lighting apparatus A4 of this embodiment, a plurality of LEDchips 2 may be covered with one sealing resin member 3. It is preferablethat such LED chips 2 emit light of different wavelengths from oneanother, such as red light, blue light, and green light. This will makeit possible for the LED lighting apparatus A4 to output a plurality ofkinds of light different in color in each pixel.

The sealing resin member 3 includes a columnar portion 31 and a domeportion 32. The columnar portion 31 is in a shape of a column having anaxial center extending in the z direction, and its cross section iscircular, for example. The columnar portion 31 is in contact with themain surface 1 a of the substrate 1, and covers the LED chip 2 and thetwo wires 25. The dome portion 32 is formed on the top surface of thecolumnar portion 31 and has an upwardly bulging shape. In thisembodiment, the dome portion 32 is hemispherical.

In this embodiment, the top surface of the columnar portion 31 is notflat but slightly recessed downward. The bottom surface of the domeportion 32 is in close contact with the top surface of the columnarportion 31. That is, the bottom surface of the dome portion 32 is notflat but slightly protrudes downward. At the interface between thecolumnar portion 31 and the dome portion 32, the outer rims of thecolumnar portion 31 and the dome portion 32 completely coincide witheach other. Specifically, the outer rim 31 a of the top surface of thecolumnar portion 31 and the outer rim 32 a of the bottom surface of thedome portion 32 completely coincide with each other. The angle (seeangle θ in FIG. 18) formed between the top surface of the columnarportion 31 (or the bottom surface of the dome portion 32) and the sidesurface of the columnar portion 31 is acute (slightly smaller than theright angle in this embodiment). The heights of the columnar portion 31and the dome portion 32 are each about 1 mm, for example.

The surface roughness (e.g., arithmetic mean roughness) of the exposedsurface (i.e., side surface) of the columnar portion 31 is larger thanthat of the exposed surface (i.e., semispherical curved surface) of thedome portion 32. This difference in surface roughness is caused by theproduction method for the LED lighting apparatus A4 (described below).

FIGS. 19 to 22 show an example production method for the LED lightingapparatus A4.

First, a plurality of LED chips 2 are mounted on the substrate 1, andtwo wires 25 are bonded to each chip (only one LED chip is shown in FIG.19). A sheet S is then stuck to the main surface 1 a of the substrate 1.The sheet S has a plurality of openings Sa. The openings Sa are eachshaped, sized, and positioned to accommodate one corresponding LED chip2. As shown in FIG. 19, the height of the opening Sa (the thickness ofthe sheet S) is set so that the LED chip 2 and the two wires 25 arecompletely housed in the inside of the opening Sa. The sheet S is madeof a fluorocarbon resin, for example, but the invention is not limitedto this.

Thereafter, as shown in FIG. 20, each opening Sa of the sheet S isfilled with a liquid resin material using a nozzle Nz, etc. The fillingamount of the resin material is set to an amount with which at least theLED chip 2 and the two wires 25 are covered with the resin material, andpreferably an amount with which the surface of the resin material is incontact with the top end of the sheet S. Note however that, in order toavoid an overflow of the resin material from the opening Sa, an amountwith which the surface of the resin material is slightly curved inwardas illustrated is preferred. The filled resin material is exposed toheat or UV to harden the resin material, thereby obtaining the columnarportion 31.

Subsequently, as shown in FIG. 21, the sheet S is removed from thesubstrate 1. The side surface of the columnar portion 31 is constitutedby the inner side surface of the opening Sa of the sheet S, and thus thesurface roughness of the side surface of the columnar portion 31 dependson the surface roughness of the opening Sa. The opening Sa is formed bypunching, for example. Therefore, the inner side surface of the openingSa is rough compared with a smooth liquid surface formed by surfacetension, for example, and the side surface of the columnar portion 31has similar roughness.

Subsequently, as shown in FIG. 22, a liquid resin material is droppedonto the top surface of the columnar portion 31 using a nozzle Nz, etc.The drop amount of the resin material at this time is an amount withwhich the resin material covers at least the entire top surface of thecolumnar portion 31, and preferably an amount with which the resinmaterial takes a dome shape. The resin material is exposed to heat or UVto harden the resin material, thereby obtaining the dome portion 32. Thesurface of the dome portion 32 is smooth compared with the side surfaceof the columnar portion 31.

Next, the workings of the LED lighting apparatus A4 will be described.

In the LED lighting apparatus A4, with the dome portion 32 provided onthe columnar portion 31, the distance between the top surface of thesealing resin member 3 and the LED chip 2 can be increased. For sealingresin members 3 whose top surfaces are the same in shape, thedirectionality can be more enhanced as the distance of the top surfacefrom the LED chip 2 is longer.

While contributing to increase in the height of the sealing resin member3, the columnar portion 31 does not increase the size of the sealingresin member 3 as viewed in the z direction. It is therefore possible tomake the LED lighting apparatus A4 compact while achieving improvementin the brightness of the LED lighting apparatus A4.

The columnar portion 31 has a size large enough to cover the entire LEDchip 2 and the entire wires 25. Therefore, at the formation of the domeportion 32, the shape of the dome portion 32 is prevented from becomingdeformed due to the LED chip 2 and the wires 25.

The top surface of the columnar portion 31 is not flat but slightlyrecessed downward. The bottom surface of the dome portion 32 is in closecontact with the top surface of the columnar portion 31. That is, thebottom surface of the dome portion 32 is not flat but slightly protrudesdownward. At the interface between the columnar portion 31 and the domeportion 32, the outer rims of the columnar portion 31 and the domeportion 32 coincide with each other. Specifically, the outer rim 31 a ofthe top surface of the columnar portion 31 and the outer rim 32 a of thebottom surface of the dome portion 32 coincide with each other. Thereason is that, as shown in FIG. 22, with the outer rim 31 a of thecolumnar portion 31, the dropped resin material is prevented fromspreading beyond the outer rim 31 a at the formation of the dome portion32. Using such a technique, the dome portion 32 can be made to bulge inthe z direction without fail and also prevented from unduly spreadinglaterally beyond the columnar portion 31.

Since the angle θ (see FIG. 18) formed between the interface between thecolumnar portion 31 and the dome portion 32 and the side surface of thecolumnar portion 31 is acute, the resin material can be made to stay onthe top surface of the columnar portion 31 by surface tension at theformation of the dome portion 32. This contributes to formation of theupwardly bulging shape of the dome portion 32, and eventually toimprovement in the brightness of the LED lighting apparatus A4.

FIGS. 23 and 24 show two alterations of the LED lighting apparatus A4.

In an LED lighting apparatus A4′ shown in FIG. 23, the columnar portion31 includes the above-described fluorescent material, but the domeportion 32 includes no fluorescent material and is transparent. Incontrast to this, in the alteration shown in FIG. 24, only the domeportion 32 includes the above-described fluorescent material, and thecolumnar portion 31 includes no fluorescent material and is transparent.

As described above, the sealing resin member 3 may be configured toentirely include a fluorescent material, or partly include it (as in thealterations shown in FIGS. 23 and 24).

FIG. 25 shows an LED lighting apparatus according to the fifthembodiment of the invention. The LED lighting apparatus A5 of thisembodiment is different from the above-described embodiments in having ashading layer 8. The shading layer 8 is joined to the main surface 1 aof the substrate 1 and has a plurality of openings 8 a (only one openingis shown in FIG. 25). The opening 8 a houses the columnar portion 31 ofthe sealing resin member 3.

Such a shading layer 8 is provided by leaving the sheet S shown in FIG.20 behind in its state of being joined to the substrate 1, for example.In this case, it is preferable that the sheet S be opaque. The droppingof the resin material as shown in FIG. 22 is performed with the sheet Skept joined to the substrate 1.

In this embodiment, having the shading layer 8, light leakage from theside surface of the columnar portion 31 is prevented. Also, since thetrouble of removing the sheet S used for formation of the columnarportion 31 is saved, the LED lighting apparatus A5 can be producedefficiently.

The shading layer 8 is not limited to the configuration described above.For example, after the process steps shown in FIGS. 19 to 22, gapsbetween any adjacent columnar portions 31 may be filled with an opaqueliquid resin (e.g., a white resin), and the resin is then hardened, toform the shading layer 8.

FIG. 26 shows an LED lighting apparatus according to the sixthembodiment of the invention. In the LED lighting apparatus. A6 of thisembodiment, the sealing resin member 3 has a coupling base layer 33. Thecoupling base layer 33 covers most of the main surface 1 a of thesubstrate 1 and also covers the plurality of LED chips 2. A groove 33 ais formed in the coupling base layer 3. Portions of the coupling baselayer 33 separated from one another by the groove 33 a constitute theplurality of columnar portions 31.

FIG. 27 shows an LED lighting apparatus according to the seventhembodiment of the invention. In the LED lighting apparatus A7 of thisembodiment, a plurality of recess portions 1 c are formed on thesubstrate 1 (only one recess portion is formed in FIG. 27). The recessportion 1 c has a circular cross section and houses the LED chip 2, thetwo wires 25, and the columnar portion 31.

The substrate 1 is obtained in the following manner, for example: thebase 11 is formed as a laminated body of a plurality of layers, and thewiring pattern 12 is formed inside the base 11. An opening is providedthrough a layer of the base 11 constituting the main surface 1 a, toobtain the recess portion 1 c. The wiring pattern 12 is formed on thetop surface of a layer of the base 11 constituting the reverse surface 1b. As shown in FIG. 27, the die bonding pad 12 a and the wire bondingpad 12 b are located on the bottom of the recess portion 1 c.

The LED chip 2 is die-bonded to the die bonding pad 12 a, and the twowires 25 are bonded to the LED chip 2. Thereafter, the recess portion 1c is filled with a liquid resin material. By hardening the filled resinmaterial, the columnar portion 31 is obtained. A resin material isdropped onto the top surface of the columnar portion 31 and thenhardened, to obtain the dome portion 32.

FIGS. 28 to 34 show an LED lighting apparatus according to the eighthembodiment of the invention. The LED lighting apparatus A8 of thisembodiment includes a substrate 1, a plurality of LED chip 2, aplurality of sealing resin members 3, a plurality of cases 4, anauxiliary substrate 5, and a cover 7.

The substrate 1 supports the plurality of LED chips 2, and has powersupply paths for allowing the plurality of LED chips 2 to emit light.Specifically, as shown in FIG. 33, the substrate 1 has a base 11 and awiring pattern 12. The plurality of LED chips 2 are mounted on a mainsurface 1 a of the base 11.

The size of the substrate 1 is about 116 mm in the x direction and about55 mm in the y direction, for example. The size of the substrate 1 inthe z direction is 0.5 mm to 1.5 mm, for example: it is about 1.0 mm,for example.

The base 11 is made of an insulating material. In this embodiment, thebase 11 is a laminated body having a plurality of layers, and each layeris made of a glass epoxy resin, for example.

The wiring pattern 12 is formed on the main surface 1 a and reversesurface 1 b of the base 11 and inside the base 11. The wiring pattern 12may have a single-layer structure made of a metal such as Cu, Pd, Ni,and Au, or have a laminated structure of a plurality of layers. For thewiring pattern 12 having a laminated structure, it is preferable thatthe surface layer be made of Au. The wiring pattern 12 has a pluralityof die bonding pads 12 a and a plurality of wire bonding pads 12 bformed on the main surface 1 a of the base 11. As will be describedlater, the die bonding pads 12 a are arranged such that each die bondingpad is located at an apex of a triangle.

A resist layer 13 is formed on the main surface 1 a. The resist layer13, made of an insulating resin, has a plurality of circular openingsfor exposing the die bonding pads 12 a and the wire bonding pads 12 b.The diameter of the openings is about 2.9 mm, for example.

The plurality of LED chips 2 are separately die-bonded to the pluralityof die bonding pads 12 a of the wiring pattern 12 on the main surface 1a of the substrate 1. In this embodiment, as will be understood fromFIG. 28, the plurality of LED chips 2 are arranged such that each LEDchip is located at an apex of a triangle. The length of one side of thetriangle is about 8.0 mm, for example.

As shown in FIG. 33, each LED chip 2 has a semiconductor layer 20, anupper electrode 21, and a lower electrode 22. The semiconductor layer 20has a structure of an n-type semiconductor layer, an active layer, and ap-type semiconductor layer placed on top of one another. In thisembodiment, the semiconductor layer 20 is made of an AlInGaNpsemiconductor and a GaAs semiconductor, for example, so that the LEDchip 2 emits infrared light.

The upper electrode 21 is formed on the top surface of the semiconductorlayer 20. Ends of two wires 25 are bonded to the upper electrode 21. Theother ends of the two wires 25 are bonded to the wire bonding pad 12 b.These wires 25 extend in the opposite directions from the LED chip 2.The lower electrode 22 is formed on the bottom surface of thesemiconductor layer 20 and joined to the die bonding pad 12 a with aconductive joining material 26.

The plurality of sealing resin members 3, each covering onecorresponding LED chip 2, are made of a transparent material (e.g., anepoxy resin or a silicone resin) that transmits light from the LED chips2. Each sealing resin member 3 also covers the two wires 25.

The cases 4 are provided for reflecting part of light emitted from theLED chips 2 upward in the z direction. In this embodiment, the cases 4are formed by applying A1 evaporation coating to a white polycarbonateresin, for example. The invention is however not limited to this. If asufficient reflectivity is secured, the cases may be formed of only awhite resin or only a metal, for example. As shown in FIGS. 31 to 33,each case 4 has two reflecting faces 4 a adjacent to each other. Eachreflecting face 4 a has a ring shape surrounding the correspondingsealing resin member 3. The reflecting face 4 a is a concave curvedsurface, and, in this embodiment, an aspheric surface. As shown in FIG.33, the reflecting face 4 a is larger in height than the sealing resinmember 3.

As shown in FIG. 28, the plurality of cases 4 are arranged to correspondto the plurality of sealing resin members 3 (eventually to the pluralityof LED chips 2). As shown in FIGS. 32 and 34, two protrusions 41 areformed in each case 4. The two protrusions 41 are placed between the tworeflecting faces 4 a at positions apart from each other in the directionperpendicular to the direction in which the two reflecting faces 4 a areapart. The two protrusions 41 do not overlap either of the tworeflecting faces 4 a as viewed in the z direction.

As shown in FIG. 34, each protrusion 41 engages with a fixing hole 11 aformed through the substrate 1, whereby the case 4 is secured withrespect to the substrate 1. In this embodiment, the protrusion 41 has afixed-diameter portion 41 a and a large-diameter portion 41 b. Thefixed-diameter portion 41 a fits in through the fixing hole 11 a of thesubstrate 1. The large-diameter portion 41 b, constituting a tip portionof the protrusion 41, expands from the reverse surface 1 b of thesubstrate 11. The large-diameter portion 41 b is larger in diameter thanthe fixing hole 11 a, thereby preventing the protrusion 41 from comingout of the fixing hole 11 a. Such a large-diameter portion 41 b can beformed by forming a rod-shaped portion having a fixed diameter on thecase 4, inserting the rod-shaped portion through the fixing hole 11 a ofthe substrate 1, and then deforming the tip of the rod-shaped portion byheating, i.e., heat caulking, for example. In this embodiment, the case4 is secured to the substrate 1 with the two protrusions 41, with noadhesive used.

The auxiliary substrate 5 includes a base (made of a glass epoxy resin,for example) and a wiring pattern formed on this base. A plurality ofelectronic components and two connectors 52 are mounted on the auxiliarysubstrate 5. FIG. 35 is a plan view of the auxiliary substrate 5, andFIG. 36 is a bottom view thereof. As shown in FIG. 29, the auxiliarysubstrate 5 is placed apart from the substrate 1 to face the reversesurface 1 b of the substrate 1. In this embodiment, the auxiliarysubstrate 5 is in parallel with the substrate 1. The auxiliary substrate5 and the substrate 1 are coupled to each other with four coupling rods53. Also, a plurality of conductive rods 54 are attached to theauxiliary substrate 5 and the substrate 1. Each conductive rod 54includes a conductive member made of a metal, and the conductive memberis covered with an insulating coating, for example. The conductive rod54 is connected to an appropriate position of the wiring pattern 12 ofthe substrate 1 and an appropriate position of the wiring pattern of theauxiliary substrate 5.

The plurality of electronic components 51 are for lighting up theplurality of LED chips 2, and include ICs for drive control, chipresistors, and diodes, for example. In this embodiment, the plurality ofelectronic components 51 include a plurality of capacitors 51 a. Thesecapacitors 51 a have a function of storing electric power for allowingthe plurality of LED chips 2 to emit light with high brightnesssimultaneously. As shown in FIGS. 29, 30, 35, and 36, part of theplurality of capacitors 51 a are mounted on one surface of the auxiliarysubstrate 5 while the remainder of the capacitors 51 a on the othersurface thereof.

The two connectors 52 are used when the LED lighting apparatus A8 isincorporated in a traffic information system, for example. As shown inFIGS. 29 and 36, the two connectors 52 are mounted on one surface(surface opposite from the substrate 1) of the auxiliary substrate 5.

The cover 7, made of a transparent resin, for example, is provided tocover the plurality of sealing resin members 3 and the plurality ofcases 4. In FIG. 28, the cover 7 is represented by the two-dot chainline. The cover 7 has a function of protecting the plurality of sealingresin members 3 and the plurality of cases 4. The surface of the cover 7may be machined (e.g., fine prisms may be formed) to refract lightemitted from the plurality of LED chips 2 in a specific direction.

As shown in FIG. 33, part of the light emitted from the LED chip 2 isoutput upward through the dome portion 32 of the sealing resin member 3.At this time, with the upwardly bulging dome portion 32, thedirectionality of the output light is enhanced so that the light travelin the z direction. The other part of the light emitted from the LEDchip 2 is reflected by the reflecting face 4 a after having been outputfrom the columnar portion 31 of the sealing resin member 3, whereby thelight travels upward in the z direction. In this way, most of the lightemitted from the LED chip 2 can be directed toward the object to beilluminated.

The upper electrode 21 and the wire bonding pad 12 b are connected bythe two wires 25. Therefore, a large current can be supplied to the LEDchip 2, and this contributes to improvement in the brightness of the LEDlighting apparatus A8. Also, with the two wires 25 extending in theopposite directions from the LED chip 2, deterioration in the shape ofthe sealing resin member 3 can be avoided.

The reflecting face 4 a has a ring shape as viewed in the z directionand also has an aspheric shape. Therefore, the reflecting face 4 a canreflect light from the LED chip 2 efficiently in the z direction.

The case 4 is made of a resin member subjected to metal coating. Theresin member can be easily formed into a desired shape and size. Themetal coating contributes to enhancement in the reflectivity of thereflecting face 4 a.

With a plurality of LED chips 2 mounted on the substrate 1, ahigh-brightness light source device emitting planar light can beprovided. With a plurality of cases 4 spaced from one another, even ifan individual case 4 is thermally deformed at use, the substrate 1 canbe prevented from being unduly deformed.

Since the plurality of LED chips 2 are arranged such that each LED chipis located at an apex of a triangle, planar light with a uniformbrightness distribution can be output.

The case 4 is secured to the substrate 1 with the protrusions 41engaging with the fixing holes 11 a of the substrate 1. Therefore, thecase 4 can be secured to the substrate 1 without fail. Also, at the timeof thermal deformation, it is possible to prevent or reduce such anoccurrence that the case 4 and the substrate 1 may affect each other.

With the two protrusions 41 located between the two adjacent reflectingfaces 4 a, the case 4 can be secured to the substrate 1 in balance.Also, with the provision of the protrusions 41, the case 4 can beavoided from increasing in size. Since the protrusions 41 do not overlapthe reflecting faces 4 a as viewed in the z direction, the reflectingfaces 4 a can be prevented from undue deformation in the process of heatcaulking for attaching the case 4 to the substrate 1.

With the auxiliary substrate 5 provided on the side of the substrate 1opposite to the side on which the plurality of LED chips 2 are provided,a plurality of electronic components 51 can be placed without blockingoutput of light. Also, since the auxiliary substrate 5 is apart from thesubstrate 1, a plurality of electronic components 51 can be provided onboth surfaces of the auxiliary substrate 5. The capacitors 51 a has afunction of storing electric power required for allowing the pluralityof LED chips 2 to emit light with high brightness simultaneously.Therefore, providing a larger number of capacitors 51 a is suitable forimprovement in the brightness of the LED lighting apparatus A8. Theplacement in this embodiment, in which a number of capacitors 51 a areprovided on both surfaces of the auxiliary substrate 5, is thereforeadvantageous in brightness improvement.

The LED lighting apparatuses according to the invention are not limitedto the embodiments described above, and the specific configurations ofthe components of the devices can be freely changed in design in variousways.

As described above, a plurality of LED chips may be covered with onesealing resin member. Such a plurality of LED chips may be three LEDchips emitting red light, green light, and blue light, for example. TheLED chips may be of a flip chip type using no connection wire.

Variations of the present invention will be listed as follows assupplementary appendixes.

[Appendix 1]

An LED lighting apparatus including:

an LED substrate having a main surface;

an LED chip provided on the main surface of the LED substrate; and

a sealing resin member made of a material that transmits light from theLED chip, the member covering the LED chip,

wherein the sealing resin member includes a columnar portion that is incontact with the main surface and a dome portion that is formed on thecolumnar portion and bulges in a direction in which the main surfacefaces.

[Appendix 2]

The LED lighting apparatus of appendix 1, wherein the columnar portioncovers the entirety of the LED chip.

[Appendix 3]

The LED lighting apparatus of appendix 2, further including a wirebonded to the LED chip, wherein

the columnar portion covers the entirety of the wire.

[Appendix 4]

The LED lighting apparatus of appendix 1, wherein the columnar portionis circular in cross section.

[Appendix 5]

The LED lighting apparatus of appendix 1, wherein the columnar portionand the dome portion respectively have a top surface and a bottomsurface that are in contact with each other, and an outer rim of the topsurface and an outer rim of the bottom surface coincide with each other.

[Appendix 6]

The LED lighting apparatus of appendix 5, wherein the angle formedbetween the top surface of the columnar portion and the side surface ofthe columnar portion is acute.

[Appendix 7]

The LED lighting apparatus of appendix 1, wherein the surface roughnessof the columnar portion is larger than the surface roughness of the domeportion.

[Appendix 8]

The LED lighting apparatus of appendix 1, wherein the sealing resinmember includes a fluorescent material, and, by being excited by lightfrom the LED chip, the fluorescent material emits light different inwavelength from the light from the LED chip.

[Appendix 9]

The LED lighting apparatus of appendix 8, wherein only the columnarportion includes the fluorescent material.

[Appendix 10]

The LED lighting apparatus of appendix 8, wherein only the dome portionincludes the fluorescent material.

[Appendix 11]

The LED lighting apparatus of appendix 1, further comprising a shadinglayer supported by the main surface of the LED substrate, wherein theshading layer surrounds the columnar portion and also shades light fromthe LED chip.

[Appendix 12]

The LED lighting apparatus of appendix 11, wherein the shading layer ismade of a resin sheet joined to the main surface.

[Appendix 13]

The LED lighting apparatus of appendix 11, wherein the shading layer ismade of a resin fed to fill a portion surrounding the columnar portion.

[Appendix 14]

The LED lighting apparatus of appendix 1, wherein the substrate has arecess portion recessed from the main surface, and the columnar portionis housed in the recess portion.

[Appendix 15]

The LED lighting apparatus of appendix 1, further including a reflectingface surrounding the sealing resin member.

[Appendix 16]

The LED lighting apparatus of appendix 15, further including a casesupported by the LED substrate, and the reflecting face is constitutedby the case.

[Appendix 17]

The LED lighting apparatus of appendix 16, wherein the reflecting facehas a ring shape as viewed in the thickness direction of the LEDsubstrate and has an aspheric shape.

[Appendix 18]

The LED lighting apparatus of appendix 16, wherein the case includes aresin member and a metal coating formed on the resin member.

[Appendix 19]

The LED lighting apparatus of appendix 1, further including an auxiliarysubstrate and a plurality of electronic components provided on theauxiliary substrate,

wherein the auxiliary substrate is apart from the LED substrate, and theplurality of electronic components are provided for activating the LEDchip.

[Appendix 20]

The LED lighting apparatus of appendix 19, wherein the auxiliarysubstrate is in parallel with the LED substrate.

[Appendix 21]

The LED lighting apparatus of appendix 19, wherein the plurality ofelectronic components are mounted on two surfaces of the auxiliarysubstrate.

[Appendix 22]

The LED lighting apparatus of appendix 19, wherein the plurality ofelectronic components include a capacitor.

[Appendix 23]

The LED lighting apparatus of appendix 19, further including aconnector, wherein the auxiliary substrate has a surface facing the LEDsubstrate and a reverse surface opposite to the surface, and theconnector is mounted on the reverse surface of the auxiliary substrate.

[Appendix 24]

An LED lighting apparatus including:

an LED substrate having a main surface and a reverse surface;

a plurality of LED chips provided on the main surface of the LEDsubstrate;

a plurality of light-transmissive sealing resin members covering theplurality of LED chips; and

a plurality of cases provided on the main surface of the LED substrate,

wherein each of the plurality of sealing resin members includes acolumnar portion that is in contact with the main surface and a domeportion that is formed on the columnar portion and bulges in a directionin which the main surface faces, and

each of the plurality of cases includes two reflecting faces, and eachof the reflecting faces surrounds one of the plurality of LED chips.

[Appendix 25]

The LED lighting apparatus of appendix 24, wherein each of the pluralityof LED chips is located at an apex of a triangle.

[Appendix 26]

The LED lighting apparatus of appendix 24, wherein a plurality of fixingholes are formed through the LED substrate, and

each of the cases includes a fixed-diameter portion and a large-diameterportion larger in size than the fixed-diameter portion, thefixed-diameter portion sits inside one of the plurality of fixing holes,and the large-diameter portion engages with the reverse surface of theLED substrate.

[Appendix 27]

A production method for an LED lighting apparatus, including the stepsof:

preparing an LED substrate having a main surface on which an LED chip ismounted;

joining a sheet having an opening to the LED substrate so that theopening can house the LED chip inside;

filling the opening with a first resin material;

hardening the first resin material to form a columnar portion having asurface facing in the same direction as that in which the main surfacefaces;

dropping a second resin material onto the surface of the columnarportion; and

hardening the second resin material to form a dome portion.

[Appendix 28]

The production method for an LED lighting apparatus of appendix 27,further including the step of removing the sheet from the LED substrateafter the step of hardening the first resin material and before the stepof dropping the second resin material.

The invention claimed is:
 1. A LED module comprising: a substrate having an obverse surface and a reverse surface and formed with a first opening and a second opening each being open to outside of the substrate at least at the obverse surface; a first electrode including a first portion and a second portion connected to the first portion, the first portion being formed on the obverse surface of the substrate, the second portion being formed within the first opening; a second electrode spaced apart from the first electrode and including a third portion and a fourth portion connected to the third portion, the third portion being formed on the obverse surface of the substrate, the fourth portion being formed within the second opening; a LED chip mounted on and electrically connected to the first electrode; a first wire connecting the LED chip to the second electrode; and a resin member made of a material that transmits light from the LED chip, the resin member covering the LED chip, the first electrode and the second electrode in plan view, the resin member bulging in a direction in which the obverse surface of the substrate faces, wherein the third portion of the second electrode is greater in size than the fourth portion of the second electrode in plan view.
 2. The LED module according to claim 1, further comprising a second wire electrically connected to the second electrode.
 3. The LED module according to claim 2, wherein each of the first wire and the second wire has an end connected at the obverse surface of the LED chip.
 4. The LED module according to claim 2, wherein the first wire and the second wire are covered with the resin member in plan view.
 5. The LED module according to claim 1, wherein each of the first opening and the second opening is elongated in the direction in which the obverse surface of the substrate faces.
 6. The LED module according to claim 1, wherein the first electrode comprises an additional conducting portion electrically connected to the second portion, and the first portion and the additional conducting portion are spaced apart from each other via the second portion.
 7. The LED module according to claim 6, wherein the additional conducting portion and the first portion are flat and parallel to each other.
 8. The LED module according to claim 6, wherein the additional conducting portion is closer to the reverse surface than to the obverse surface of the substrate.
 9. The LED module according to claim 1, wherein the second portion of the first electrode has an upper end face that is flush with the obverse surface of the substrate.
 10. The LED module according to claim 9, wherein the upper end face of the second portion is held in contact with a bottom surface of the first portion of the first electrode.
 11. The LED module according to claim 1, wherein the first portion of the first electrode has a series of a first edge, a second edge and a third edge that are spaced apart from the LED chip, and the third portion of the second electrode has a fourth edge, a fifth edge and a sixth edge that face the first edge, the second edge and the third edge, respectively.
 12. The LED module according to claim 1, wherein the first portion of the first electrode is greater in area than the LED chip in plan view.
 13. The LED module according to claim 1, wherein the substrate is greater in size measured along the direction in which the obverse surface of the substrate faces than the LED chip.
 14. The LED module according to claim 1, wherein the LED chip comprises an upper electrode to which the first wire is bonded.
 15. The LED module according to claim 1, wherein the LED chip has a rectangular shape in plan view, and a distance between the second portion of the first electrode and the fourth portion of the second electrode in a direction parallel to an edge of the rectangular shape is greater than a length of the LED chip in the direction parallel to the edge. 